Abstract: Techniques are provided for selectively refreshing a materialized view. A portion of a materialized view is refreshed (or updated) while other portions of the materialized view are not refreshed. Thus, the other portions of the materialized view may contain “stale” data that does not accurately reflect current data in the base table(s) upon which the materialized view is based. In one technique, a user indicates the portion of the materialized view that is to be refreshed. In another technique, a user indicates a plurality of portions of a materialized view and it is automatically determined which portion should be refreshed first. Change data that indicates information about changes made to different portions of one or more base tables and/or read data that indicates information about reads to different portions of the materialized view may be taken into account to determine which portion of a materialized view to refresh.

Abstract: Techniques are provided for performing a refresh or update of a materialized view without modifying the materialized view. Such a refresh is referred to as an out-of-place materialized view refresh. An out-of-place materialized view refresh involves creating one or more outside tables into which data will be inserted. During the refresh, the materialized view may be accessible for query processing, even though the materialized view contains “stale” data. After the insertion, the one or more outside tables are made accessible for query processing and future queries will target the one or more outside tables instead of the materialized view.

Abstract: Techniques are provided for performing a refresh or update of a materialized view without modifying the materialized view. Such a refresh is referred to as an out-of-place materialized view refresh. An out-of-place materialized view refresh involves creating one or more outside tables into which data will be inserted. During the refresh, the materialized view may be accessible for query processing, even though the materialized view contains “stale” data. After the insertion, the one or more outside tables are made accessible for query processing and future queries will target the one or more outside tables instead of the materialized view.

Abstract: Techniques are provided for selectively refreshing a materialized view. A portion of a materialized view is refreshed (or updated) while other portions of the materialized view are not refreshed. Thus, the other portions of the materialized view may contain “stale” data that does not accurately reflect current data in the base table(s) upon which the materialized view is based. In one technique, a user indicates the portion of the materialized view that is to be refreshed. In another technique, a user indicates a plurality of portions of a materialized view and it is automatically determined which portion should be refreshed first. Change data that indicates information about changes made to different portions of one or more base tables and/or read data that indicates information about reads to different portions of the materialized view may be taken into account to determine which portion of a materialized view to refresh.

Abstract: A technique for refreshing materialized views in a database is disclosed. The detail table is partitioned, and changes made to the detail table are tracked with information stored, for example. Only sections in the materialized view which correspond to the partitions which include modifications made to the detail table are refreshed, thus avoiding the need of a complete refresh to overcome staleness.

Abstract: A method and system for updating both partition change track tables and non-partition track tables in a materialized view. A log-based incremental refresh is performed on the materialized view and a partition change tracking based refresh is performed on the materialized view. The dependency of the materialized view log for the partition change track base table is removed.

Abstract: An approach for processing a query in a database system is disclosed. An original query is determined to be partially satisfied by a materialized view. The original query is transformed using a set operation (i.e., union and intersection) on the materialized view and either another materialized view or a base table.

Abstract: A method and system for updating both partition change track tables and non-partition track tables in a materialized view. A log-based incremental refresh is performed on the materialized view and a partition change tracking based refresh is performed on the materialized view. The dependency of the materialized view log for the partition change track base table is removed.

Abstract: A method and system for enhancing a materialized view. In one embodiment the method includes analyzing a defined query of the materialized view, checking the requirements of the materialized view log, generating execution scripts that automatically create and enhance the materialized view logs and tuning the materialized view.

Abstract: A technique for refreshing materialized views in a database is disclosed. The detail table is partitioned, and changes made to the detail table are tracked with information stored, for example. Only sections in the materialized view which correspond to the partitions which include modifications made to the detail table are refreshed, thus avoiding the need of a complete refresh to overcome staleness.

Abstract: An optimizer for a data transformation system. The optimizer optimizes data flow plans that describe how data is to be transformed from the form it has in a data source to the form required in a data destination. A data flow plan is made up of a sequence of transforms, and the optimized data flow plan is equivalent to the original data flow plan but has fewer transforms. One kind of optimization is read/write optimization, in which the data flow plan is modified so that operations of the original data flow plan are performed in the data source or destination. Another is merge optimization, in which a single merge transform specifies the operations specified in a plurality of the transforms of the original data flow plan. The operations specified in the merge transform can further be performed in parallel. The optimizer additionally reorders the transforms in the original data flow plan to increase the amount of optimization.